Metals in SF Estuary

Only US estuary with systematic, long-term monitoring

Most peer-reviewed publications of any US estuary

(Sañudo-Wilhelmy et al., 2004)

Metals in SF Estuary

OLD NEWS

(Sañudo-Wilhelmy et al., 2004)

Environmental ResearchPollutants in SF Bay (Sept. 2007)

Synthesis of decades of high quality data - truly remarkableonly possible for SF Bay

Multiplicity & Diversity of Institutions - truly remarkableacademia (UCD, UCSC, Maryland)state & federal agencies (SWRCB, USGS, USF&WS)ngo’s (SFEI)industry (AMS, CH2MHill, Tetra Tech)

Articles on Metals in Special Issue

Buck et al. - copper Yee et al - nickelFlegal et al. - silver Conaway et al. - mercurySchoellhamer et al. - sediments Anderson et al. - toxicityThompson et al. - toxicity

Other new reports: Black et al. (2007) MMHg Complexation Huerta-Diaz et al.(2007) Metals in Porewater Luengen et al. (2007) Metals & Plankton Conaway et al. (in press) Hg Review (in press) …………

Metals in SF BayLots of Interest & Lots of Data

(Buck et al., 2007)

Comparability of RMP Data

Trace metal clean tech.

valid

Rigorous QA/QC

statistical analyses

Evolving methodologies

intercalibrated

Published - sci. journals

accessible reproducible

(Ndung’u et al., 2006)

Total Dissolved (< 0.45 µm)* Copper

* Historic basis for water quality criteria (Cu in SF Bay > WQC)17 - 44% decline throughout the estuary (1993-2001)positively correlated with DOC (p < 0.0005)

Consistent with complementary speciation measurementsorganic ligands typically bind >99.9% dissolved Cu in SF Bay

Site-specific criteria for copper in SF Bay are being developed (Buck et al., 2007)

Nickel

Ni concentrations ~ constant (1992-2005)

Most “total dissolved” Ni is also strongly complexed

Water quality objectives for Ni also being reconsidered

(Yee et al., 2007)

Silver

Temporal decrease in Central & South Bayswater & sediments & biotaconcentrations may still be toxic

Temporal increase in northern reachnew inputs or increased remobilization?

(Flegal et al., 2007)

Mercury

*Significant (p<0.05) decrease of Hg in sediments @ 8 locations (1993-2001)

NO associated decrease of Hg in sport fish or bivalvesHg(total) ≠MMHgrelative increase in MMHg production ?

(Conaway et al., 2007)

Sediments ~ Metals

Pronounced temporal & spatial variability of metals~ sediment fluxes

Suspended sediments (SSC) a proxy for metalsfaster & cheaper

BUT sediment transport in the Bay is changingnegative sediment budget

(Schollhamer et al., 2007)

How can things be worse - when they’re better ?

reduced contemporary industrial inputs +

negative sediment budget -

erosion of surface sediments -

increased remobilization of historic inputs ?

(Conaway et al., 2005)

How can things be worse - when they’re better?

on-going inputs of contaminated sedimentshistoric & contempporary

SF Bay is a trap for metals continuous recycling of metals

metals never degrade

(Steding et al., 2000)

Summary

Hg is toxic in SF Bay (biota & humans)

Cu appears to still be toxic in sediments

Ag may still be toxic in sediments

Cd may still be toxic in sediments

Metal toxicity may be increasing in SF Bay

Acknowledgments

USGS (McColluch, Conomos, Peterson, Nichols, …)

SF-RWQCB (Carlin, Ritchie, Mumley, Taberski, …)

AMS (Spies, Gunther, Salop, Johnson,…)

SFEI (Thompson, Hoenicke, Davis, Yee, Lowe, Sedlak, …)

Funding Agencies, Municipalities, Industries (Tucker, …)